24-h personal monitoring of exposure to Power Frequency Magnetic Fields in adolescents – Results of a National Survey

Objectives The aim of this exposure assessment study was to gain information about the exposure levels of adolescents in Israel to power frequency (50 Hz) magnetic fields (MF) through personal monitoring, and to provide reliable data for national policy development. Methods 84 adolescents, 6–10th grade students, carried an EMDEX II meter attached to their body for 24 h. The meter recorded the MF every 1.5 s. The students documented their activities and microenvironments, such as apartment (awake or asleep), school, transportation, open public areas and other indoor environments. Results The geometric mean (GM) of the daily time weighted average (TWA) of all the participants was 0.059 μT (STD = 1.83). This result is similar to those of personal exposure surveys conducted in the UK (GM 0.042–0.054 μT), but lower than levels found in the US (GM 0.089 − 0.134 μT). The arithmetic mean was 0.073 μT, 23% higher than the GM. Fields were lowest at school (GM 0.033 μT), and average outdoor exposures were higher than indoor ones. 3.6% of the participants were exposed to daily TWA above 0.2 μT. The typical time spent above 0.2 μT ranged from few minutes to few hours. The time spent above 0.4 μT and 1 μT were much shorter, around 1–15 min and from few seconds to 2 min, respectively. Momentary peaks ever recorded were in the range of 0.35–23.6 μT Conclusions Exposure of adolescents in Israel is similar to data reported in other countries, being below 0.1 μT for the vast majority, with very few average exposures above 0.2 μT. Analysis of the different microenvironments allows for a cost-effective and equitable policy development.